Seville vs Madrid

Sounds like a good idea to me. The best of Madrid are the art museums. That would be the main reason to go to Madrid. Sevilla has excellent flamenco (my fave is Casa de Flamenco), the best tapas in Spain, and some lovely sights with Moorish influence - especially the Alcazar. Do a day trip to Cordoba to see the Mezquita and wander the Juderia.

If you want to squeeze in Granada, it can be done, but it will shorten your time in Sevilla and Barcelona, both with lots to see and do. For Granada you'll need 2 nights, take the train or bus from Sevilla, then fly to Barcelona.

If you're interested in the Moorish influence, you should prioritize Granada with Alhambra. If you do decide to go to Madrid, the Royal Palace is amazing!

You're likely to face really hot weather in August down in Andalucia (average high in Seville is over 100F), but it should be bearable for a few days. Madrid Is likely to be uncomfortably hot also, but not as bad as Seville. Just prepare yourself mentally.

Thanks everyone. I didn't know it got so hot in Andalusia in Aug. Unfortunately I might pass this time and save it for a later trip with Morroco.

Thanks for the suggestions!

I would think long term here, visiting Seville without Granada would be a real shame. I would vote for Barcelona + Madrid and save Andalusia for a another trip when you have time to do it right. They are more suited for a longer trip where it would not require jumping through so many transportation hoops just to get where you are going. Personally I love Madrid, I have stated here many times it's one of the most underrated large cities in Europe, along with Budapest and Lisbon. It's a lot more than just the art, too. We were last in Seville in September 2005 and it was quite warm but tolerable. Barcelona was very humid as well and I broke down and bought some shorts. One good thing about Madrid is that it is at elevation, so it might be a little cooler. The timeanddate.com site now has weather averages.

I don't know if Madrid will be much less hot than Andalucia. I just looked at daily temps in August 2016 and 2015, they were from 32-37C. Ignore average temps - they tell you nothing.

Then I looked at Valencia - about 5 degrees less, sounds pretty comfortable for August. So I'd spend one day in Madrid for the main sights and then head to the more temperate Costa Brava. . . and save Andalucia for winter (lovely in February) or early spring.

Note: first paragraph edited.

Wundergroind weather website has month to month historical weather data. I use this to determine mostly my wardrobe, but also temps during my travel dates of interest. Check the last 3 years to get a feel for the real trends.
Madrid alows a home base for several day trips to places if it doesn't appeal to you. Toledo, segovia, or the Alcazar. Barcelona may allow a day or teo at the beach or Montserrat. In those seven days, jet lag may hit allow some flex time but both these cities offer lots of options.

I wouldn't let weather considerations guide your choice of one place over another. Averages are just that, averages. It is still quite possible you strike a hot spell in a place that on average has lower temps for August.

If you go to Seville, 'Five Places to Shop in Seville'.